Antacid suspensions are standard medications for the treatment of heartburn and other gastrointestinal disorders. Antacids neutralize the gastric acids created in the stomach. It is desirable that an antacid feature a high acid neutralization capacity and a rapid rate of gastric acid neutralization.
Antacids are available in the form of liquid suspension or solid dosage forms. A major benefit of the liquid antacid form is that it acts more quickly than a solid to neutralize gastric acid. A disadvantage associated with antacids in general (both liquid and solid forms) is an undesirable chalky taste.
It is known in the art that conventional milling or homogenizing of antacid suspensions alleviates the chalkiness to some degree but not entirely. For example, U.S. Pat. No. 4,533,543 (Morris et al.) describes improving the texture of solid antacid formulations by maintaining a small particle size, e.g. less than 500 millimicrons, and coating the particles with a mixture comprised of a fatty material or oil. U.S. Pat. No. 3,843,778 (Diamond) also discloses coating solid antacid particles, ranging in size from 0.05 to 300 microns, with an oil to create an improved texture.
French Patent 2,512,344 discloses an antacid suspension of aluminum hydroxide or magnesium hydroxide added in powder form to water, in which the powder is then mechanically fragmented and dispersed until the mean particle size is 5-10 microns. International Application PCT/US93/11720 discloses an antacid composition comprising particles consisting essentially of an aluminum-based neutralization agent, e.g. aluminum hydroxide, wherein the particles are in discrete crystalline form. The particles have an average particle size of less than about 3 microns. Coarse particles of aluminum-based neutralizing agent are dispersed in a liquid media in which it is insoluble and subsequently ground to achieve the desired particle size. The antacid composition may contain from 5 to 80% by weight of said particles.
U.S. Pat. No. 3,892,851 (Hinkel) describes a clear antacid solution comprising water and an effective amount of polymeric meglumine-hexitol-aluminum hydroxide complex. In some formulations the composition must stand for two weeks before it becomes clear. Hinkel teaches that polymeric meglumine must be present for a clear antacid solution to be formed.
It is known in the art to use linear polyols, such as mannitol and sorbitol, with aluminum hydroxide gels to inhibit the polymerization reaction that occurs on aging. Shah et al., 70 J. Pharm. Sci. 1101-1104 (Oct. 1981), teaches that polyols also have a negative effect on the action of aluminum hydroxide gels by reducing the rate of acid neutralization, which occurs when the aluminum hydroxide concentration is correspondingly reduced. Shah discloses that by carefully selecting a specific polyol and corresponding concentration, gel stabilization can be optimized.
There is a need in the art to provide a liquid antacid composition of aluminum hydroxide gel that is non-chalky and translucent in appearance. Translucency appeals to the patient or user because it connotes purity and good mouth feel, as opposed to the chalky, granular taste normally associated with liquid antacids. There is also a need for simple and economical preparation of such formulations, which do not require long periods of time for the solution to clear.